This commit extends the `v1/authorization` package to support
passwords associated with a token.
The summary of changes include:
* authorization.Service implements influxdb.PasswordsService
* Setting passwords for authorizations
* Verifying (comparing) passwords for a given authorization
* A service to cache comparing passwords, using a weaker hash
that will live in memory only. This implementation is copied
from InfluxDB 1.x
* Extended HTTP service to set a password using
/private/legacy/authorizations/{id}/password
Closes #
Yiqun (Ethan) Zhang
Stuart Carnie